The present invention relates to an embossed fabric and a method for making it.
Pile fabrics formed by flocking or other methods are frequently embossed to form a wide range of surface patterns and textures. Ordinarily embossing a pile fabric is achieved by running the fabric through a single cylinder bearing an engraved pattern and subjecting the pile surface to selective amounts of heat, pressure and time embossed with the various parameters determined in part by the type of pile fabric treated. Of particular importance is the engraving cylinder upon which the pattern being embossed is formed. There are basically three types of engraving techniques used to form patterns on these engraving cylinders. They are (a) film photo engraving, which uses an acid etch; (b) mill and dye tooling engraving; and (c) router engraving; which includes both mechanical and hand tooled applications. The choice of each results in an engraved cylinder having different characteristics from the others.
In the film photo engraving, which is predominantly used for fabricating wall coverings and foil wraps using vinyl or vinyl coated papers, a cylinder is made having the capability of very shallow embossing at low heat and pressure. A cylinder capable of shallow embossing, known in the trade as kiss embossing, is ordinarily achieved by acid etching a pattern on a steel or copper cylinder. The pattern is engraved by selectively wrapping the embossing steel or copper cylinder with a special film and thereafter exposing the wrapped cylinder to an acid bath which etches the steel or copper only in areas where the metal is exposed to duplicate the desired pattern. Although steel or copper cylinders are ordinarily used for film photo acid etch engraving, brass will, on occasion, be used to make small cylinders or rolls for specialized applications. Ordinarily the use of brass cylinders or rolls is avoided because the cost is prohibitive. The range of the engraved depth obtained on a steel base cylinder or roll varies from about 0.003 to 0.035 of an inch, while a copper base cylinder or roll has a slightly deeper range of engraving depth possibility of up to 0.050 of an inch. To some extent the engraving depth that is achieved is dependent upon the characteristics of the particular design to be engraved. In general the use of this film photo etch engraving technique to form cylinders or roll for embossing pile fabric is rarely selected because the depth of engraving is too shallow for a permanent embossed design.
A second type of engraving involves a mill and dye tooling engraving technique. Ordinarily mill engraving is effected primarily on steel cylinders although it may also be used on copper or brass cylinders. Steel is preferred because copper does not stand up well to the high heat and pressures ordinarily used during the embossing process for upholstery fabric while brass is cost prohibitive for this type of application.
In the mill and dye tooling engraving process, a hand crafted cutting tool is used for the actual pattern to be engraved. The depth of the engraving in the cylinder is dependent upon the configuration of the pattern. The actual object size, line thickness and spacing of the pattern to be engraved determines or limits the engravers ability to achieve depth. Ordinarily, the depth achieved ranges from 0.002 to 0.060 of an inch. One limitation in utilizing mill engraved cylinders for embossing is the engraving depth while another is pattern repeat size. In a furniture upholstery fabric application this is quite relevant since the repeat size relates to the usefulness of a particular design used for furniture upholstery. A 54 inch repeat would be considered a full repeating pattern. A 27 inch repeat would be considered a half repeating pattern. In this type of engraving, with few exceptions, the largest pattern typically engaged is much smaller and usually is an all-over texture. In many cases the technique is used for all-over textures which do not have pattern repeats and thus can be applied to furniture fabric in any manner or direction required. For example, a background striation type of pattern is possible.
A third type of engraving technique, routing engraving, is used to engrave patterns with larger repeat sizes or patterns that require greater depths of engraving. A full repeat of 54 inches may be engraved and depending on the pattern configuration, engraving in the order from 0.060 of an inch to 0.200 of an inch on a cylinder is achievable. In this routing engraving process, the embossing cylinder is ordinarily a brass based cylinder rather than steel based cylinders. Steel based cylinders can be used, but the hand tooled routing technique is very time consuming and costly. Depending on the particular design and the desired end result the additional cost of hand tooled router engraving may be justified. Steel base cylinders are not ordinarily used for mechanical routing applications because the steel is too hard and brittle and has a tendency to break or crack when deep engraving is required. In the mechanical routing process a film is wrapped about the brass embossing cylinder or roll bearing the exact pattern to be engraved. The cylinder or roll is cut with an overhead milling machine that is ordinarily manually operated to engrave the pattern outlined on the film. Because the engraving on the cylinder is achieved manually on brass, a much deeper cut in the cylinder is achievable. Hand tooled router engraving typically involves the use of either a steel or brass cylinder or roll. Again the film is wrapped around the cylinder or roll to be engraved, but in this case the technician uses strictly hand tools to cut out and engrave the design. Routing engraving is typically used to engrave patterns with large repeat size and great depth of engraving a full repeat of 54 inches can typically be engraved into a cylinder or roll, depending upon the pattern configuration with a depth of anywhere from about 0.060 of an inch to 0.200 of an inch. The advantage of the routing technique is that due to the depth of engraving that can be achieved, the unembossed areas in the pile surface are never exposed to the high heats and pressure associated with the embossing process. Thus, the free ends of the pile under the deep embossed area of the cylinder do not touch the cylinder surface. The end result is that the finished fabrics exhibit a far superior overall improvement in xe2x80x9chandxe2x80x9d than when other types of engraving are used.
Heretofore, embossing cylinders have been used that were engraved by acid etching, mill engraving or router engraving to form patterns on flocked or pile fabric. It has, also, been not uncommon in the industry to combine on one embossing cylinder or roll a design formed in part by acid etching and in part by mill engraving. Insofar as is known this technique has not been used to emboss pile type fabrics. Also, insofar as is known, embossing cylinders have not been heretofore made by combining either mill or acid etch in combination with routing engraving (hand or mechanical) engraving techniques in a single cylinder to emboss pile fabrics.
In the manufacture of upholstered, embossed fabric one common problem that has plagued the industry relates to the shiny, glossy, flat areas that are created when a pile surface is embossed. These shiny, glossy, flat surface areas make the fabric look cheap and reduce the overall value of the material. It has been customary to try to avoid these shiny, glossy, flat areas by further processing the embossed goods through a wet or dry processing, or, alternatively use designs that exhibit fine areas only of embossing. The washing processes, however, are relatively costly and often make the fabric of limited commercial value because of costs involved. On the other hand, utilizing patterns with limited embossing areas for small embossed patterns limit the scope of marketable product. These problems have developed primarily when using router engraved cylinders alone.
The problems of fabrics with these glossy flat areas is particularly acute in flocked fabrics using synthetic fibers because the high heat and pressure used during the embossing process plasticize the synthetic fibers, resulting in a shiny area. Additionally, when embossing woven, knitted or tufted pile fabrics the fabric can initially be formed with an irregular pile surface area or texture, which when embossed reduces the undesirable shiny effect.
It is therefore an object of the present invention to provide an improved pile fabric which can be made with a wide range of patterns of large repeat size and without costly processing after the fabric has been embossed. A further object of the present invention is to provide an improved embossed pile fabric that is relatively simple to manufacture and which is less likely to encounter rejection in the manufacturing process. It is, also, an object of this invention to obtain a very soft hand with a texture in the background that eliminates the unfavorable shiny areas in the embossed pattern.
In the present invention a pile fabric is embossed using an overall non-repeating or repeating texture design engraved on an engraved steel or brass cylinder or roll using a mill and dye tooling or, for very shallow embossing, an acid etch technique to create a background for an embossed design, and a foreground or pattern, in turn, formed by a router engraving technique.
The process utilized uniquely combines two or more separate and distinct designs having different levels of engraving depths to achieve a texture and finish that is uncommon in flocked velvets or other pile fabrics and particularly flocked fabrics. In the present invention, the finer detail of elements achievable by use of mill tool or, in some cases, acid etch engraving on a cylinder or roll is combined with the deeper engraving advantages of a router engraving technique on the same cylinder or roll to produce a bold well-defined or clean cut pattern with a soft overall hand.
It is thus an object of this invention to provide a method of making a pile upholstered fabric having a wide variety of pattern applications with the patterns well defined and the fabric having a soft overall hand.
A further object of this invention is to provide an improved means and method of forming a pile fabric embossed using an embossing cylinder or roll having a background pattern defined by mill engraving or acid etch engraving techniques and a foreground pattern formed by a routing engraving technique, either mechanical or hand tooled or a combination of both.
Another object of this invention is to provide an embossing cylinder or roll having a surface defined in part by mill tool engraving or acid etch technique and in part by routing engraving technique either mechanical or hand tooled or a combination of both.
Another object of this invention is to create a pile fabric with a very soft hand which has a textured background and which eliminates the unfavorable shiny areas in the embossed pattern.
A still further object of the present invention is to provide an improved method of embossing a flocked fabric using an engraving cylinder having a background formed by an acid or mill engraving technique and a foreground pattern formed by a routing engraving.
One more object of the present invention is to provide a method of forming an embossed surface on a pile fabric in which a background pattern is embossed with an embossing roll defined by an acid or mill engraved area and foreground area is defined by a routing engraved area having a depth greater than the depth of the pile fibers.
A still further object of the present invention is to provide an engraving cylinder made of steel or brass and having at least one area engraved by an acid or mill routing technique to form a background pattern and a second area engraved by a routing technique to form a foreground pattern.
Another object of the present invention is to produce a soft embossed pile fabric utilizing a flocked fabric consisting of synthetic pile fiber which has been embossed with a multilayer cylinder produced with a mill and dye of acid etch technique combined with a router technique.
In the present invention in a preferred form, there is provided an embossed flocked fabric which preferably may have a total weight in the order of 6.5 to 9.0 ozs., per square yard, and a pile weight in the order of 1.0 to 3.5 ozs., per square yard with the fabrics preferably having a denier in the order of 0.6 to 3.5 DPF (denier per filament) and with the flocked fabrics embossed in a pattern having a background and foreground with the background formed with a mill tool or acid etch engraved pattern on the cylinder or roll and the foreground formed with a routing engraved pattern on the same cylinder or roll.